The present invention is directed to data processing systems, and in particular to a method, and apparatus for implementing that method, of protecting files carried by a storage medium from inadvertently being modified, changed, or deleted.
In computing systems there are often created sensitive, system-critical files that must remain inviolate and/or protected against inadvertent modification. One example, and one to which the present invention is directed, of a system-critical file is an audit trail file that is used to track the history of changes made to a database. The audit trail file can be relied upon to reconstruct the database should it, for whatever reason, become corrupted, or otherwise lost. The application program or "process" responsible for managing and maintaining the database will periodically make changes or modifications to the managed database (e.g., adding or modifying a record, etc.). Each such change or modification to the database will result in the creation of an audit record to reflect the change. The audit record is appended to the associated audit trail file kept on disk.
Should some other process not associated with the audit trail file for some reason inadvertently modify or delete it, the likelihood exists that the ability to reconstruct the associated database has been lost. For this reason the audit trail file must be protected from inadvertent changes that will affect the ability to correctly reconstruct the associated data base. Thus, while read-only access may be granted to an audit trail file of a database (or other maintained data segment/structure), any modifying access to that audit trail file must be limited only those processes needing such access.